What is sinus arrhythmia?

Sinus arrhythmia is characterized by the normal fluctuation of the heart rate that occurs in sync with the respiratory cycle in healthy children. During inhalation, the heart rate typically increases, while it decreases during exhalation. This phenomenon is a physiological response that showcases the body's ability to regulate heart rate in accordance with the demands of respiration, highlighting the integration of the cardiovascular and respiratory systems.

In children, sinus arrhythmia is considered a normal variant and is often more pronounced in younger populations. This variability in heart rate is generally benign and reflects a healthy autonomic nervous system. Understanding this concept is vital for differentiating between normal physiological responses and pathological conditions that may present with irregular heart rhythms.